Detection of rotaviruses in the day care environment by reverse transcriptase polymerase chain reaction

Detection of poliovirus, hepatitis A virus, and rotavirus from sewage and ocean water by triplex reverse transcriptase PCR

A triplex reverse transcriptase PCR (RT-PCR) was developed to simultaneously detect poliovirus, hepatitis A virus (HAV), and rotavirus in sewage and ocean water. Sewage and ocean water samples seeded with the three different viruses were concentrated by ultrafiltration. The unseeded ocean water and sewage samples were concentrated by vortex flow filtration and/or ultrafiltration. Random hexamers and a rotavirus downstream primer were used to initiate reverse transcription. Three different sets of primers specific for poliovirus, HAV, and rotavirus cDNAs were mixed in the PCR mixture to amplify the target DNA. Three distinct amplified DNA products representing poliovirus, HAV, and rotavirus were identified by gel electrophoresis as 394-, 192-, and 278-bp sequences, respectively. Dot blot and Southern analyses were used to confirm the amplified products for each virus present in the environmental samples. Except for poliovirus, the sensitivity of triplex RT-PCR for the detection of rotavirus and HAV was found to be similar to that of monoplex RT-PCR, which uses only one set of primers to amplify a single type of virus. The triplex RT-PCR has greater advantages over monoplex RT-PCR for virus detection, namely, the rapid turnaround time and cost effectiveness.

Infectious diarrhoea in children: controlling transmission in the child care setting

An increase in the number of preschool children cared for within groups in child care centres has been associated with increasing numbers of women in the workforce. Children at this age are at high risk for gastrointestinal diseases caused by a large number of enteric pathogens, and the risk is increased by the greater potential for person-to-person transmission within group care. This report considers the pathogens that may cause diarrhoeal illness in children, with particular reference to those that have been reported in formal day care settings. The major risk factors for transmission of these agents and a high rate of diarrhoeal illness in the child care setting include attendance of non-toilet-trained children, staff combining nappy changing and food preparation duties, large enrollment, low staff-to-child ratio, and poor hygiene and child handling practices. Investigations undertaken during an outbreak of diarrhoea have frequently used limited diagnostic testing, often suitable for identifying only bacterial and protozoal agents. Such limited investigations have tended to incriminate agents that have prolonged carriage and are easily identifiable in standard microbiology laboratories. Finding a pathogen in these circumstances needs to be interpreted with caution. Prevention and control measures include training and education in good personal hygiene, emphasis on the need for frequent handwashing, separation of change areas from food handling and eating areas, routine cleaning and disinfection of environmental surfaces and personal items, and exclusion of any child or child care worker with diarrhoea.

Simple method of concentrating enteroviruses and hepatitis A virus from sewage and ocean water for rapid detection by reverse transcriptase-polymerase chain reaction

A rapid and simple method was developed to detect enteroviruses and hepatitis A virus (HAV) in sewage and ocean water. Sewage samples were concentrated by Centriprep-100 and Centricon-100 at 1,000 x g. Samples collected from estuary and near-shore surf zone ocean water in Southern California were concentrated by vortex flow filtration and microconcentration. Reverse transcriptase-polymerase chain reaction (RT-PCR), with enterovirus primers or HAV capsid-specific primers, was used to detect enteroviruses or HAV in all concentrated samples. A nonradioactive internal probe was used to confirm the amplified products. Results of seeding experiments indicated that at 4 degrees C, HAV was more persistent than poliovirus in seawater and both HAV and poliovirus persisted longer at 4 degrees C than at 25 degrees C. RT-PCR was at least 500-fold more sensitive than cell culture. Results were obtained within 5 h by RT-PCR, in contrast with the 5 days to 3 weeks required for cell culture.

Outbreaks of food-borne and waterborne viral gastroenteritis

Norwalk virus infection is the epidemiologic prototype for outbreaks of food-borne and waterborne gastroenteritis. Around the world, Norwalk virus and Norwalk-like viruses appear to be major causes of food-borne and waterborne illness. Assessment of the overall significance of viral agents to the epidemiology of food-borne and waterborne illness is hampered by the lack of surveillance throughout much of the world. In areas where food-borne and waterborne illness surveillance is conducted, outbreaks of viral gastroenteritis are underreported because of the lack of availability of routine laboratory services to confirm the viral etiology. Routine use of epidemiologic criteria as an alternative to laboratory confirmation will allow better assessments of the importance of viral gastroenteritis until effective laboratory methods can be widely implemented. Outbreaks of viral gastroenteritis have been propagated by contamination of water supplies, raw foods, and ill food handlers. Controlling an outbreak depends on identifying and removing the source of contamination. The demonstrated occurrence of person-to-person transmission and the likely occurrence of transmission of Norwalk-like viruses by aerosol make it necessary to evaluate the potential for transmission by food handlers and servers in every outbreak, regardless of primary source.